CVE-2021-43074: Fortinet FortiOS

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

An improper verification of cryptographic signature vulnerability [CWE-347] in FortiWeb 6.4 all versions, 6.3.16 and below, 6.2 all versions, 6.1 all versions, 6.0 all versions; FortiOS 7.0.3 and below, 6.4.8 and below, 6.2 all versions, 6.0 all versions; FortiSwitch 7.0.3 and below, 6.4.10 and below, 6.2 all versions, 6.0 all versions; FortiProxy 7.0.1 and below, 2.0.7 and below, 1.2 all versions, 1.1 all versions, 1.0 all versions may allow an attacker to decrypt portions of the administrative session management cookie if able to intercept the latter.

Affected products

• Fortinet FortiOS: from 6.0.0, before 6.4.9 (fixed in 6.4.9); from 7.0.0, before 7.0.4 (fixed in 7.0.4)
• Fortinet FortiProxy: from 1.0.0, before 2.0.8 (fixed in 2.0.8); from 7.0.0, before 7.0.2 (fixed in 7.0.2)
• Fortinet Fortiswitch: from 6.0.0, before 6.4.11 (fixed in 6.4.11); from 7.0.0, before 7.0.4 (fixed in 7.0.4)
• Fortinet FortiWeb: from 6.0.0, before 6.3.17 (fixed in 6.3.17); from 6.4.0, before 7.0.0 (fixed in 7.0.0)

Published 2023-02-16. Last modified 2026-06-17.